Dear (manager name),
I hereby tender my resignation from my position as Sales Director.
I am writing you to officially tender my resignation from (company name) effective Thursday, July 17th, 2006.
Working for (company name) has been a wonderful experience. I could not ask for a better group of colleagues. I have grown in many ways here and will always treasure the opportunities provided for me by (company name).
I will be accepting a position as (position) with (company name). While I will miss my friends here at (company name), I feel that it is time for a new challenge and experience.
If you have any questions, please feel free to ask.
Best Wishes,